A novel Confocal Modulation System is being developed to conveniently attach to and convert almost any conventional microscope into a confocal microscope having innovations and unique combined capabilities including; l) Choice of reflection, fluorescence, and transmission confocal imaging, 2) User-selectable illumination and imaging from partial view fields, 3) Variable speed imaging potentially beyond 1000 frames/sec, 4) External gating and control of illumination and image acquisition, 5) Choice of white light or laser illumination, 6) Automatic correction of field distortion, 7) No moving parts to degeneratively mis-align. The specific aims of Phase II are to build and test a fully functional prototype module based on the successful analytic optical modeling and sub-component feasibility studies completed under Phase I. Aberration, contrast, and resolution will be analyzed photometrically on a variety of optical evaluation targets and on real biological specimens in order to optimize the system for general and specialized applications. A PC-compatible interface and image-processing software will be developed to take full advantage of the optical design, enable ratio imaging, and integrate with other commercial imaging tools. The system should enable new studies of intracellular ion concentrations, synaptic activity, cell proliferation and metastasis, kidney tubule function, and intracellular kinetics.